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Updated on May 19, 2023
6 min read

Fractured Cusp

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What is a Fractured Cusp?

A fractured cusp is a very common dental injury. Cusps help you chew and give your teeth anatomy. Most molars have four or five cusps.

fractured cusp

The top portion of a tooth, or tooth cusp, can fracture due to tooth decay or injury. Fortunately, modern dentistry offers numerous ways to prevent a fractured cusp.

These treatments can help restore your teeth in the event of a fracture. Speak to your general dentist to see what treatment is best for you. 

Other Types of Tooth Fractures

Aside from a fractured cusp, there are four other types of tooth fractures. It is always essential to get a proper diagnosis from your dentist on what type of tooth fracture you have. 

The type of treatment, its cost, and your oral health standing will also depend on what type of fracture you have. 

The other types of tooth fractures are: 

1. Craze lines 

Craze lines are superficial tiny cracks in the enamel. They usually occur in adult teeth, don’t cause any immediate harm, and are monitored by your dentist.

2. Split tooth 

A split tooth is caused by tooth decay or an injury that causes two distinct segments. Extraction is usually required if the tooth can’t be salvaged.

3. Vertical root fracture 

This type of crack begins below the gum line and extends to the tooth's surface. These range in severity and may not cause symptoms until the tooth becomes infected.

Root fractures commonly occur from dental trauma. Extraction is usually required in these cases. 

4. Cracked tooth 

A cracked tooth can result from an injury, tooth grinding, or chewing hard foods. Depending on the extent of the tooth crack, a root canal, crown, and/or extraction may be needed. 

What Causes a Fractured Cusp?

There are plenty of factors that can cause the structure of your teeth to soften. For example, recurrent decay weakens teeth, potentially causing cracks.

Fractured Cusp 3-d Depiction

The most common causes of a fractured cusp include:

  • Severe tooth decay 
  • Bruxism (chronic teeth grinding/clenching) 
  • Trauma 
  • Failed dental restorations, including dental crowns and bridges 
  • Biting into hard foods or items 

Symptoms of a Fractured Tooth Cusp

Symptoms may vary depending on the severity of your fractured cusp. If you have a small chip, you may be unaware your tooth has a fracture. 

On the other hand, larger fractures can be painful and require a visit to the dentist. Common symptoms of a fractured tooth include:

  • Temperature sensitivities
  • Sharp edge of your tooth detected by your tongue 
  • Sharp pain when chewing
  • Gum discomfort

Usually, fractured cusps in adult teeth do not injure the pulp or require repair. When a broken cusp only affects the chewing surface, it may not cause any symptoms. 

Does a Fractured Cusp Hurt?

A fractured cusp does not always cause pain. But if the fracture is severe enough, it can be painful.

Inside each tooth, there is a soft inner tissue called the pulp. The pulp contains the tooth’s nerves and blood vessels.

When a tooth is fractured, chewing can cause the pieces to move and irritate the pulp. Eventually, the pulp may become too damaged to heal itself.

Once damaged, the tooth can become sensitive to extreme temperatures. A cracked tooth can start hurting all by itself after a while. If left untreated, extensive cracks can lead to infected pulp tissue, which can spread to the bone and gums.

How is A Fractured Cusp Diagnosed?

Dentists have different methods to diagnose cracks and fractures early. These methods include:2 

  • Clinical examination — A careful clinical examination to locate periodontal defects and damaged segments of teeth.
  • Visual inspection — Visual detection of fractures and carious lesions in primary and permanent teeth. 
  • Exploratory excavation — Involves removing an existing filling or cavity or crack to determine the extent of the crack
  • Percussion test — A cracked tooth could be diagnosed with a positive response to apical percussion.
  • Dye test — Fracture lines can be highlighted with methylene blue or gentian violet stains.
  • Transillumination — Involves shining a light over the affected area for abnormalities.
  • Bite test — Involves biting onto different materials to determine the location and severity of a fracture. 
  • Radiograph — Uses X-rays and bitewing imaging to determine overall tooth status.

Fractured Cusp Treatment

If you have a fractured cusp, you will benefit from various treatments to help avoid pain and infection. The recommended treatment depends on the severity and extent of the fracture.

Treatment for a fractured cusp can range from non-invasive to extensive work. Common treatments include:

  1. Dental filling 
  2. Dental crown 
  3. Dental inlay or onlay 
  4. Root canal treatment

Severe cracks can also be treated with tooth extractions and implants. If there is significant damage to your tooth, you may be referred to an endodontist.

When is a Fractured Cusp an Emergency?

If you fracture a cusp of your tooth, do not panic. There are very few dental emergencies that cannot be easily managed at home before your dental visit. 

However, early diagnosis and treatment are always important to avoid a dental emergency. Visit your dentist immediately if you experience any of the following:

Do Fractured Teeth Heal Completely? 

If you have a fractured tooth, it will not heal on its own. Unlike other bones in your body, teeth require some restoration treatment to avoid ongoing problems. 

Once treated, most teeth continue to function normally. Without treatment, the crack can worsen, resulting in pain, infection, or tooth loss.

How to Prevent Tooth Fractures

Sometimes tooth trauma is unpreventable. Fortunately, there are a few ways you can help prevent tooth fractures in certain situations. For example: 

  1. Wear an athletic mouthguard when you play sports to avoid trauma 
  2. Consider getting a custom night guard if you grind your teeth while sleeping
  3. Visit your dentist regularly
  4. Avoid biting into hard objects or foods

It’s also a good idea to complete unfinished dental treatment as soon as possible. If you wait too long, more complex oral health issues can arise, such as an injury or tooth loss. 


A fractured cusp happens when the top portion of a tooth is damaged from an injury or tooth decay. Other types of cracks can affect teeth, but they are usually treatable.

A fractured or cracked tooth can cause pain, discomfort, and sensitivity. If left untreated, it can lead to tooth loss and infection.

While fractures do not always cause pain, a severe fracture can be painful. Lastly, a fractured tooth cannot heal on its own and will require some type of treatment.

Last updated on May 19, 2023
6 Sources Cited
Last updated on May 19, 2023
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Cracked teeth.” American Association of Endodontists.
  2. Zidane, B. “Recent Advances in the Diagnosis of Enamel Cracks: A Narrative Review.” Diagnostics (Basel, Switzerland), 2022.
  3. Kakka, A., et al. “Treatment of cracked teeth: A comprehensive narrative review.” Clinical and experimental dental research, 2022.
  4. Lee, T., et al. “Characteristics, Treatment, and Prognosis of Cracked Teeth: A Comparison with Data from 10 Years Ago.” European journal of dentistry, 2021.
  5. Zhang, C., et al. “A method of crack detection based on digital image correlation for simulated cracked tooth.” BMC oral health, 2021.
  6. Morimoto. S., et al. “Risk Factors Associated with Cusp Fractures in Posterior Permanent Teeth—A Cross-Sectional Study.” Appl. Sci., 2021.
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